An organic light-emitting diode (OLED) device has attracted attention and research from more and more researchers due to its multiple advantages of low manufacturing cost, full-solid state, active light emission, high brightness, high contrast, being low-voltage direct current driven, low power consumption, wide viewing angle, high response speed, small thickness, wide range of operating temperatures, being capable of implementing flexible display and the like. Especially, due to the characteristic of flexible display, the OLED device can be bent and thus is widely applied in fields needing curved-surface display, such as smart cards, electronic paper, smart labels and the like, and is gradually becoming a new favorite in the field of display technology.
Generally, an OLED device at least includes an anode, a cathode and a luminous layer between the anode and the cathode, wherein the cathode is generally made of an active metal, and the luminous layer is generally made of an organic light-emitting material. The organic light-emitting material and the cathode in the OLED device are particularly sensitive to water vapor and oxygen, so water vapor and oxygen blocking requirements of the OLED device are relatively high. For example, suppose the service life of the OLED device is 10,000 hours, and the permeability of the water vapor and the permeability of the oxygen through OLED device encapsulation are calculated on the basis of minimums of water vapor quantity and oxygen quantity required for failure of low work functions (e.g. a work function of magnesium and a work function of calcium), and it is obtained that the water vapor permeability of a material for OLED device encapsulation is required to be less than 10−6 g/m2/day, and the oxygen permeability is required to be less than 10−5-10−3 cm3/m2/day.
The OLED device generally adopts a plastic substrate as a flexible substrate, and as the plastic substrate has relatively high water vapor and oxygen (hereinafter simply referred to as water oxygen) permeability, a barrier film needs to be manufactured in the flexible substrate to prevent the permeation of water oxygen. At present, the barrier film is generally formed by means of depositing a silicon nitride material (SiNx) and a silicon oxide material (SiOx) in the flexible substrate; because SiNx and SiOx are both inorganic materials, cracks are easily produced in the bending process; moreover, to prevent the water oxygen from permeating into the OLED device through pin holes, SiNx and SiOx need to have certain thicknesses to achieve the effect of blocking water and oxygen, whereas the probability of producing cracks is further increased due to the increase of thicknesses of SiNx and SiOx films. The barrier film cracks may lead to defects of the OLED device. Generally, when the OLED device has a defect, the defect of a thin film transistor (TFT) in the OLED device is easily determined from the change of electrical performance; whereas the defects caused by cracks of the barrier film in the OLED device need to be observed with a microscope, and observation by using the microscope has the problems that sample preparation is complex, a defect point is difficult to be found, a long time is consumed and the like, leading to not only low detection efficiency, but also low accuracy of detection result, and thus the process step causing the defect cannot be effectively controlled, thereby resulting in a relatively low rate of qualified product of the OLED device.